Abstract: Being one of the most serious microvascular complications of diabetes, diabetic retinopathy(DR) is the leading cause of new cases of blindness among adults. Though the pathogenesis of DR still remains to be completely elucidated, increasing evidences suggest that microglial cells play an important role in the occurrence and development of DR. This review expect to summary the changes of distribution, morphology, surface marker profile and function of microglial under physiological condition and diabetic background, and to further explore the physiological conditions of neurovascular unit in the function and regulation of  microglial and its possible mechanism involved in DR. (Int Rev Ophthalmol, 2013, 37: 358-Ⅱ)